ИСТИНА

Research of ice regime Russian rivers is an important scientific and practical task due to specific of geographical location and climate conditions of the country. Ice phenomena are observed on rivers of the European territory of Russia (ETR) annually during 5 month and more. In the ETR the rise of air temperature in the cold season has resulted in more frequent winter thaws. In recent decades a significant change of spring flood features has observed. In the rivers of the north of the ETR the features of spring runoff didn’t change significantly. But a decrease of the maximum discharges of the spring flood in the Volga and Don drainage basins is typical. In the current study hydrological information about the river ice break up period was analyzed. This information was based on data from more than 300 hydrological stations on the rivers of the ETR and was enabled the elevation of changes in characteristics of spring ice run and ice jam. Two periods were used for analysis: 1940 – 1975 and 1976-2011. Research of the river ice change caused by climate change was conducted for whole ETR and for the main hydrological regions. In the rivers of the north of the ETR break up date didn’t change significantly, but frequency of ice break up hazard increased. In the Volga river basin early ice run are observed even more often. During break up period ice floes were replaced by slush ice and ice jams were replaced by hanging ice dams. Break up occurs 5–10 days earlier. In the Don river basin ice run isn’t observed, but ice decays in place. Break up occurs 10–15 days earlier. For south of the ETR ice cover period wasn’t observed. Long winter thaws divide ice season into 2 and more parts.